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University of New Orleans. Honors thesis. 2000.; University of New Orleans. Dept. of Geology and Geophysics.

Abstract/Introduction

This study utilizes a database of 1,829 major, trace, and isotopic geochemical analyses from the Central American Volcanic Arc (CAVA) to investigate regional geochemical trends and their relation to tectonic and geophysical parameters of slab dip and crustal thickness. The CAVA extends 1,500 km from the Mexico-Guatemala border to Panama and is the result of subduction of the Cocos plate beneath the Caribbean plate. The Global Volcanism Program at the Smithsonian National Museum of Natural History compiled the CAVA database from an older database, CENTAM, and 175 other published papers. This research complements numerous other studies of the CAVA by presenting the arc on a larger scale. Along-arc variation of mean K20 in intermediate samples correlates with crustal thickness. Elevated mean K20 values in southeast Costa Rica is attributed to shallower dip angles. 87/86Sr vs. 143/144 Nd plots show a negative correlation (most like the mantle array) for thicker crust, but also indicate a positive correlation for thinner crust, in agreement with previous research. Across-arc variation in Honduras shows K20 increasing as distance from the trench increases, whereas La/Yb increases gradually from the volcanic front to Zacate Grande (182 km) to Tegucigalpa (272 km) in the back arc and Ba/La decreases. K20 values for the Guatemala across-arc transect show a minor increase with distance from the trench, but not as pronounced as the increase in Honduras. Ba/La slightly increases with distance from the trench in Guatemala, and La/Yb increases moderately but remains low from the volcanic front to the back arc.

Access

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Degree

B.S.

Degree Program

Geology

Department

Department of Geology and Geophysics

Thesis Advisor

Simmons, William

Advisory Committee

Webber, Karen; Blanton, Linda Lonon

Date Degree Awarded

2000;

Rights

The University of New Orleans and its agents retain the non-exclusive license to archive and make accessible this thesis in whole or in part in all forms of media, now or hereafter known. The author retains all other ownership rights to the copyright of the thesis.

Notes

vi, 48 leaves : col. ill., col. maps ; 29 cm.; typescript; "An honors thesis ... in partial fulfillment of the requirements for the degree of Bachelor of Science, with University Honors and Honors in Geology"; Thesis (B.S.)--University of New Orleans, 2000; Includes bibliographical references (leaves 46-48); December 2000; approved November 28, 2000.